Resilient flexible sheet and method of making the same



30, 29- w. A. BOUGHTON -1,722,963

RES ILIENT FLEXIBLE HEET AND METHOD OF MAKING THE SAME Filed Jan. 7, 1925 I 71 flew a r Willis a. 230 ugh 5'02? amrnev s Patented July 30, 1929.

UNITED STATES PATENT OFFICE.

WILLIS BOUGHTON, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO BENNETT BOX CO., 013 BOSTON, MASSACHUSETTS, CORPORATION OF MASSACHUSETTS RESILIENT FLEXIBLE SHEET AND METHOD OF MAKING THE SAME.

Application filed January This invention relates to resilien t'flexible sheets and methods of .making the same. More particularly it relates to material suitable for toe boxes in shoes, and for similar uses, or for other purposes to which the described material shall be found applicable. It is an object of the invention to provide a toe box material and a process of manufacture which shall be superior to the many which are already known in that it shall embody all of the various qualities which are good or desirable and shall in addition be easily controllable as to hardness, flexibility and resilience, to suit different types of shoes.

Among the desirable properties to be embodied in such a material are, that it should be low in cost; made of materials which are easily'and always available; and capable of being wiped into the shoe, so as to give a toe that is free from wrinkle, by an operation which is neither difiicult, dirty nor expensive. The finished box must lie smooth under the leather; be hard enough at its edges to hold the shape of the last and be flexible and resilient at the middle of the arch; except as these requirements may be modified in the case of soft-toe shoes. The box must become a unit with the adjacent felt and lining of the shoe; it must be adaptable to the several principal processes of manufacture of shoes, known, for example, as the McKay process, the turn shoe process, the welt process, etc.; must be reasonably waterproof; and must not weaken materiallyduring wear. In addition it must be obtainable in various degrees of thickness, stiffness and resilient power, according to the desire of the shoe manufacturer. So far as I am aware there has not heretofore been known any toe box material that caumeet all bf these requirements. The manufacturer of shoes has had to be content with being guided by the feature which he deems.

most important, and submitting to its at tendant shortcomings. The invention pro- 7, 1925-. Serial No. 1,038.

rating and coating a sheet of'cloth with a fluid material, which upon cooling or drying becomes hard and brittle with a certain degree of resilient flexibility. This brittle sheet is then worked sharply in several directions, as over a right angled edge,or is otherwise treated, so as to crackle or break the layer of brittle filler into lumps centering at the crossings of the warp and woof of the cloth. The cracks or interstices between the lumps are then filled with gum rubber, and the lumps are covered with the same, by dipping the sheet in rubber latex. After drying, the rubber thus deposited on and between the lumps acts as a resilient cushion between contacting parts. It both prevents abrasion of the lumps, by rubbing against each other, when the sheet is bent, and serves as a water-proofing coating. The latex may preferably be applied just before the sheet is lasted into the shoe. The lasting and wiping in then proceed easily; the excess of latex penetrates into the adjacent cloth, felt or leather layers of material in the toe; and when the water has evaporated all of these sections of the toe are held together by the gum, cemented into one teslight strength of resilience, that is, not capable of carrying much weight and still exhibiting its resilience. threads loosely woven, it will exhibit flexibility with a stronger resilience. When a closely woven cloth is used the resiliency is still.greater; and in thecase of cloth with large threads closely woven the resiliency is greatly increased while at the same time the flexibility is decreased. Therefore when a toe box is wanted with hard edges and a. rather stiff springy center, cloth should be chosen which is closely woven of moderately large yarn, or is otherwise full bodied. In some types of weaving such as twill, the resilience is difierent in difierentdlrections;

If it be of larger" the ridges of thread apparently gather stiffener between them in different degree in diflerent directions. This property makes it possible to prepare boxes having two different degrees of resilience, from a single kind of cloth and from uniform treatment, the differentdegree being obtained according to the way in which the grain -of the cloth is laid in the toe box. If a more yielding box but nevertheless .a springy one is required, as for womens shoes, the cloth should be closely woven of fine yarn. And if a very flexible box is wanted for a mans shoe, with slight power,of resilience, the material should be of medium sized yarn not too closely woven.

The cloth which has thus been selected ac-' cording to the ultimate result desired is to be saturated with a suitable material which has attained fluidity by the addition of heat or by-going into solution, and which upon cooling or evaporation becomes hard and brittle. In practice I have used a mixture of rosin with other gums, with or without a dye. While any suitable filler and stiffener gt the rosin type may be employed, I 'will, or illustration assume that the stiffener consists of rosin alone, applying this hot and then rolling out and cooling the sheet on a flat surface, either loose or under tension.

' The resulting sheet is resiliently flexible and can be used' for the manufacture ofshoe boxes; but it is not an ideal material because it tends to crack in lines, when dis-- torted beyond the limit of elasticity, and thus loses the property of uniformity of resilience.

Therefore it is preferred not to use the i product 'atthis stage, but the brittle filler above described is cracked or broken into an infinity of minute sections or lumps. This is accomplished'by pulling the sheet sharply back and forth over a right angled edge, or by running it between suitable rolls, thus bending it beyond its elastic limit and beyond its breaking point, so as to crackle its brittle filler. The lumps which result ap-' pear to cling tothe cloth at the crossings of its warp and woofthreads. They hold the threads together firmly; permit bending of the sheet as a whole to a marked degree before its breakage occurs; and yet still retain severelybent without exceeding the limit of elasticity. The stiifness appearsto depend very largely upon the nature of cloth used. The sheet as awhole has the qualities which are suitable for the manufacture of a resilurally to the lining of the toe and form therewith an integrated unit.

Therefore in the preferred form the next step is to fill cracks and interstices and cover the sheet with gum rubber, as by .dipping' it into rubber latex. .The latex may be 1n the concentrated commercial form or may bethickened by evaporation or diluted with water. This step is especially 'a'pphcable where the sheet has been filled with a water insoluble stiifener such as that above de-.

squeezing, and the sheet having been allowed to dry, the rubber is. found deposited not only on the surface of the sheet but also between the lumps of broken stiflfener. In this position the rubber preserves these lumpsfrom abrasion and improves the flexibility and resilience by acting as a cushion between the contacting parts when the sheet is bent. It also aids'in rendering the box waterproof; and it makes thebox more resistant to heat which may he accidentally applied to the shoe after manufacture and while it is being worn, aswhen the wearer allows his foot to rest against a steam pipe, because it tends to prevent the flowing togetherofthe separated lumps which would otherwise occur. 1 In the preferred method for this stage of the process, the material is dried into the desired shape for the toe box and then is dipped into the rubber latex just before being lasted into the shoe. Being an aqueous liquid; the latex does-not dissolve the stiffener, where a stiffener of rosin type is used, but it adheres to all surfaces thereof,

and permits of very easy lasting. The excess of latex' penetrates into the adjacent layers of-the shoe toe so that when the water has evaporated the residue of rubber cements all layersyof the toe together in close resilient form. It also acts both as a binder, helping to strengthen tlie stiffener sheet, and as a resilient prop for increasing its quality of resilient flexibility.

When the resilient sheet of the invention is bent into an arch, as in'the toe .of the .shoe, it yields to pressure but resumes its original contour when-the pressure is re-.

lieved.

The accompanying drawing illustrates certain features of the invention somewhat diagrammatically Figure 1 represents a section of woven cloth, much enlarged;

Figure 2 represents-the same impregnated with a stifiener such as the rosin composition above mentioned; 7 Figure 3 represents the same in crackled form, after it has been worked sharply over an edge as above described and Figure 1 shows the'same with its coating and filling of rubber deposited from latex.

Referring to the drawing, 10, 11,-represent respectively the warp and woof of the piece of cotton cloth, and 12 is the rosin composition applied thereto, which may be assumed to have penetrated thoroughly into the threads of the cloth and to remain as a coating on its surface in dry form; being intact in Figure 2, but broken into lumps 12' in Figure 3, with crackle spaces 12 between them. These lumps are firmly secured to the threads of the fabric by greater or less penetration of the rosin composition indicated by dots in the drawing. The depth of the surface coating of the filling material may vary, according to circumstances or prearrangement, from an inappreciable thickness to a considerable thickness. Accord- 1ngly 1n the claims the word impregnate is used man inclusive sense to refer to that filler which remains on the surface, be it little or much, as well as to that which is more intimately absorbed into the texture of the cloth. The deposit of rubber is marked 14 and appears in Figure't, being exterior to the several lumps and to the threads, yet clinging closely to them and serving as buffers between the lumps when the coated fabric is bent.

When the sheet is dipped in latex it becomes limp very quickly, Which appears to be due to a moistening of the threads of the cloth by the liquid of the latex with charac teristic action upon the fibers. After the thread is dried, making the deposit of rubber, it may in some cases be lasted without further treatment; but if the sheet is too thick or stiff a more workable temporary condition is obtained by dipping itagain in latex due probably to this reaction of the threads to the wetting.

It will be understood that the breakage of the brittle sheet is not altogether so simple and regular as is represented in the drawngs, which are to be considered approximations. It is believed that in commercial practice'the thickness of rosin layer will not usually. be as great in proportionto the thickness of yarn as the drawings indicate. Under the microscope it has been observed that the rosin layer penetrates into the yarn and is accordingly broken throughout the strand and is evidenced by a broken section having satiny appearance rather than appearing glassy with cracks, except at the crossings of threads where the masses of rosin are generally unbroken or only slightly broken. From the occasional-satiny appearance of fibers on the top or outward side of the strand at a crossing of threads it seems that the unbroken, anchoring means of rosin may be chiefly between the threads which the sheet has been subjected. Although 'the microscope shows that most of the rubber deposit from the latex is on the surface, it is evident that penetration is also present, for when 'a. sheet which has been worked is exposed to latex on one side only the latex rapidly soaks through to the other side and therefore deposits rubber in the interstices of the sheet when the latex dries.

It will be understoodthat the invention is not limited to the use of commercial rubber latex, for one may use any latex, natural or synthetic, that may serve the purpose, or any similar colloidal aqueous suspension of rubber particles resembling latex in its properties and action.

I claim as my invention:

1. A resilient flexible sheet comprising a sheet of cloth impregnated with a brittle stiffening material, which material is disseminated throughout the cloth sheet, within and on both sides thereof, in a continuous body of said material whose surface portions on both sides are cracked into minute sections.

2. A resilient flexible sheet comprising a sheet of cloth impregnated with a brittle stiffening material' which is cracked into minute sections encased in-rubber.

3. A resilient flexible sheet comprising a sheet of cloth impregnated and covered on both sides with a body of rosin which is cracked into minute sections encased in rubber.

4. A resilient flexible sheet comprising a sheet of cloth combined with lumps of a hard substance adhering thereto at the thread crossings of the cloth, said lumps being contiguous but cleft from each other by cracks.

5. A resilient flexible sheet of material comprising a sheet of cloth combined with lumps of a hard substance adhering thereto at the thread crossings of the cloth; said lumps being contiguous but cleft apart by cracks and coated with rubber.

6. A process of making a resilient flexible sheet, comprising the impregnating of a sheet of cloth with a substance in fluid form which upon hardening becomes brittle; the said impregnation being effected in such manner that a body of said hard and brittle substance remains penetrating the cloth and the surface of said substance remains upon each side of the cloth; and crackling the said brittle substance on both sides of the said brittle substance, thereby breaking it into small sections; and then dipping the sheet into a rubber depositing solution.

8. A method of making a resilient flexible sheet toe' box, comprising the im regnating con ition; bending the sheet sharply beyond the breaking point of the brittle filler at closely contiguous positions over its surface and in different directions, thereby breaking the filler into minute sections; moistening the threads of the sheet; lasting the toe while it is thus moist; and dryin the toe with the said sheet adhering to ad acent sheets in the toe.

9. A composite resilient flexible" sheet comprising a carrier sheet of supporting material and coextensive therewith layers of rosin and rubber sup rted thereon.

10. A composite resilient flexible sheet comprising a carrier sheet of supporting material and coextensive therewit layers of a flexible resilient material and a stiffening material interpenetrating the supporting material and capable of being temporarily softened' Signed at Boston, Massachusetts, this sixteenth day of December, 1924.

WILLIS A. BOUGHTON-. 

